1. Field of the Invention
This invention relates to keyboard assemblies used for acoustic musical instruments such as pianos as well as electronic musical instruments such as electronic pianos, for example. In addition, this invention also relates to methods of manufacturing the keyboard assemblies.
This application is based on Patent Application No. Hei 10-271926 filed in Japan, the content of which is incorporated herein by reference.
2. Description of the Related Art
In general, keyboard instruments such as the pianos and electronic pianos have characteristics that intensities of musical tones, which are generated using keyboards, reflect key-depression intensities. Therefore, engineers pay great attention to key-touch feelings of the keyboards such that performers are able to feel reactions of keys in response to intensities of the musical tones. Thus, it is demanded that the performer feels a heavy reaction in the motion of the key in response to "strong" key depression while the performer feels a "light" reaction in the motion of the key in response to "weak" key depression. In other words, the key provides the performer with resistance force when being depressed, wherein the resistance force varies in response to key-depression intensities applied to the key. However, it is difficult to provide variations of the resistance force of the key by elastic resistance using springs and the like. So, the variations of the resistance force of the key are actualized by inertial resistance of the key based on appropriately selected mass of the moving part(s) of the key.
In order to obtain good touch feelings of the keys of the keyboard, the moving parts of the keys should be designed to have certain degrees of mass. For this reason, a deadweight made of lead material is buried in each of the keys. Alternatively, moving parts of the key are constructed by two rotation members or more, which are interlocked with each other. Herein, each of the members is designed to have a certain degree of mass. Thus, it is possible to manufacture the keyboard which is somewhat compact in dimensions.
Conventionally, the acoustic musical instruments such as the pianos have the keyboards, which are normally designed to provide good touch feelings for the users to depress the keys. However, those keyboards are complicated in constructions and are disadvantageous because of relatively heavy weights thereof. On the other hand, the electronic musical instruments frequently use the keyboards having simple constructions. For example, the paper of U.S. Pat. No. 4,602,549 (corresponding to Japanese Patent Publication No. Sho 63-56554) discloses an example of the keyboard in which the moving parts of the keys are designed to have certain weights. However, this keyboard is not designed to provide the keys with inertial resistances in an efficient way. In addition, the paper of Japanese Patent No. 2,508,028 discloses another type of the keyboard, which is designed such that the key is interlocked with a mass body such as a hammer to increase inertial resistance. Because of relatively heavy weight of the mass body, the keyboard as a whole is likely heavy in total weight. So, it is impossible to provide improvements in touch feelings efficiently with respect to weights of the keys. As described above, it is a reality that in spite of the weights applied to the keys, the conventional keyboards are unable to provide the keys with good touch feelings. In addition, the weights are applied to all keys which range from several tens of keys to eighty-eight keys. Therefore, the conventional keyboards is likely heavy in total weights.